Drifting-valve for locomotives.



R. RBNNIE & H. R. STAFFORD.

DRIFTING VALVE FOR LOCOMOTIVES.

APPLICATION FILED SEPT 27, 1913 1 79 514 Patented Nov. 25, 1913:

2 SHEETS-SHEET l.

WITNESS S R. RBNNIE & H. R. STAFFORD.

DRIFTING VALVE FOR LOCOMOTIVES.

API'LIOATIOH FILED SEPT. 27, 1913,

1,0795 1 4;, Patented NOV. 25, 1913.

2 SHEETS-SHEET 2 UNITED STATES PATENT ROBERT RENNIE, or sco'rm, New YORK, AND HAL a. ammonia, or PLAINFIRBD, NEW messy.

DRIFTING-VALVE FOR LOCOMOTIVES.

Specification of Letters latent.

Patented Nov. 25,1913.

To all whom it may concern Be it known that we, Rossnr RENNIE, of Scotia, in the county of Schenectady and State of New York, and HAL R. STAFFORD, of Plainfield, in the county of Union and State of New Jersey, have jointly invented a certain new and useful Improvement in Drifting-Valves for Locomotives, of which improvement the following is a specification.

The object of our invention is to provide means, of sim le and inexpensive construction and ready applicability in locomotives of any of the present constructions, whereby a graduated volume of steam may be automatically admitted to the valve chests or cylinders of a locomotive engine, when drifting or running with its throttle closed, under the influence of inertia or gravity, the quantity of steam so admitted being regulated proportionally to the speed of the locomotive so as to prevent the formation of a partial vacuum in the valve chests and cylinders, and the admission of steam being so directed as to insure the feed of the lubricating material in the m st effective manner.

The improvement claimed is hereinafter fully set forth.

In the accompanying drawings: Figure 1 a is a side view, partly in section, of a locomotive engine, illustrating an application of our invention; Fig. 2, a vertical central section, on an enlarged scale, of a drifting valve mechanism embodying our invention; and, Fig. 3, a transverse section, on the line a a of Fig. 2.

In the operation of locomotives on long descending grades, it is the practice to close the throttle valve, thereby shutting off the supply of steam to the valve chests, under which condition the movements of the pistons produce partial vacuums in the cylinders, resulting in the injurious induction of hot gases and cinders into the cylinders, and by reason of the cessation of steam supply,

they are insufiiciently lubricated and their inner surfaces, as well as those of. the packing rings and piston heads, are rapidly deteriorated by a gummy de ositzof oil and dirt. This latter objectionable result is articularly serious in the case of locomotives usingmrperheatd steam. In order to pile vent this objectionable induction of smoke drifting box gases and cinders above mentioned, three different types, of devices have hereto fore been applied, viz: (a) check valves opening inwardly to the distribution valve 0 rests, and permitting the ingress of atmospheric air during the periods that a partial vacuum is otherwise formed therein; (b) by-pass or circulating appliances, whereby direct communication is established between the opposite ends of the cylinders, so that the gases therein are caused to flowpast or around the pistons at each stroke, instead of being alternately expelled and drawn in through the exhaust passages; and (c) auxiliary or driftin throttle valves, byimeans of which a smal quantity of steam is admitted to the valve chests, when the locomotive is drifting or running with the main throttle valve closed.

Appliances of the air admission type (a) are objectionable by reason of involving, in their operation, a rapid and destructive change in temperature of distribution valves,

pistons, bushings, etc., due to the introduction of air, at the temperature of the atmosphere, into passages which are highly heated by the steam, especially when superheated steam is used, thereby causing cracking or breaking of parts if sufficient air is admitted to prevent the induction of smoke box gases, or failure to prevent such induction if the supply of air is sufficiently restricted to minimize the rapid change of temperature.

The objection to by-pass appliances, type (6), consists in the inability of the gases circulated from one to the other end of the cylinders, to dissipate or carry off the heat generated by the friction of the moving parts, so that a sntlicient rise in tem-- peraturemay take place to destroy the oil or other material used for lubrication. Appliances of this type are also subject to the objectiorrof preventing the formation of a compression cushion at the ends of the stro e for relieving the strain on the crank pin due to the intertia of the reciprocating parts, the presence of which cushion is a matter of importance in large locomotives at comparatively high speed.

Auxiliary d fting valves, type a), as ordinarily constructed, graduating the quantity of steam supplied, proportionately to the speed of the locomoare incapa le of the risk of causing accitive, and subject to be closed when the locodents by failure to motive is stopped.

Our invention is designed to accom lish the useful results possible to be derived rom appliances of the several types referred to, without being subject to the'objections thereto above stated.

Referring to the drawings, in the practice of our invention We provide, in connection with each of the cylinders, 1, of the locomotive, a valve chest or easing, 2 having, on its lower end, a nozzle or tubular extension, 2", which is threaded to engage a corresfpondin ly threaded opening at one end 0 the c inder, or, as shown, in the wall of one of t e steam induction ports, 1, of the linder. The most convenient location for t is purpose is ordinarily that shown in Fig. 1, to wit, in that portion of the induction port which is formed around one of the bushings, 3, of the valve chest, 3, in which the distribution valve 4, which, in this instance, is of the iston type, reciprocates. The valve casing, 2, may, however, be connected with the cylinder, or with the induction port at any other oint in the length of the latter which may be preferred.

The upper end of the valve casing, 2, is closed by a removable head, 2", which is secured to the casing by studs, 5, and nuts, 5. An enlarged piston chamber, 2, is formed in the casing below the head, 2", and a partition, 2, extends across the casing and separates the iston chamber, 2, from the bore of the tubular extension, 2. A valve chamber, 2", whichis closed at its to bv a removable cap, 2, is formed in the ea 2 and a pipe, 6, leads from the steam space 0 the boiler into the valve chamber, 2", said pipe being preferably connected to a steam supply turret, or small domeon the boiler, and controlled by a valve within convenient reach of the engineman, in the ordinary manner of auxiliary steam supply pipes.

A pipe, 7, leads from the upper portion of the piston chamber, 2, to the steam supply space of the, distribution valve chest, 3, the connection of said pipe being preferably, as shown, made to the steam supply pipe, 3", which leadsfrom the boiler to the distribution valve chest, and its outlet being located adjacerit to that of the lubricant feed pipe, 8, in the pi e, 3, in order that the steam discharged rom it may break up and disseminate the the pipe, 8.

, Communication between the piston chamber, 2, of the casing, and the valve chamber, 2, of the head, 2, is controlled by a valve, 9, governing an opening in the inner wall of the head and having a fluted or channeled steer, 9, extending through said openlubricant entering through timed to admit sut'ficient steam ing into the piston chamber, 2. A properly packed piston, 10, is fitted in the piston chamber, 2, below the opening of the ipe, 7, thereinto, said piston, when actuated by pressure on its lower side, abutting against the stem, 9, of the valve, 9, and unseating said valve.

A hardened steel valve seat, 11, through which extends a central passage, 11', is fitted in the partition, 2, of the casing, 2, said valve seat abutting, on its upper side, against an open ended cylindrical guide, 12, which is perforated by a plurality oi peripheral openings. The opposite end of the guide, 12, abuts against, and is closed by, a plate, 13, which is held in position by a screw cap, 14, a packin ring, 14" being interposed to insure a tig t joint. A leakage port, 15, extends through the partition, 2, adjacent to the valve seat, the upper end of said port being closed by a screw plug, 15, through which a passage of smaller diameter than the leakage port is formed.

- The passage, 11, of the valve seat, 11, is controlledby a check valve, 16, fitting truly in the guide, 12, said valve being adapted to be unseated by the action of pressure upon its lower side from the tubu ar extension, 2, of the casing, and being chambered out, as shown, to reduce its weight and extend the capacity of the cushion chamber which is formed within the guide, 12, between the upper end of the valve, 16, and the plate, 13.

In the operation of the appliance, when the locomotive is running with throttle open, the pressure in the cylinders rarely rises above that in the distribution valve chests, and the valve chest pressure, acting through thepipes, 7 on the tops of the pistons, 10, in con unction with the boiler pressure in the valve chambers, 2, acting on the tops of the valves, 9, prevents said valves from being unseated, so long as the pressure in the piston chambers, 2 below the pistons, 10, is equal to, or less than, the pressure above them. When the throttle is closed, and the main cylinder pistons and distribution valves continue their cyclic motions, the pressure in the distribution valve chests immediately reduces to that of the atmosphere, or less, and during the compression periods of the piston strokes, a pressure, or plenum is created in the cylinders, which, through the tubular extensions, 2, of the valve casings, 2, and the passages, 11, of the valve seats, 11, unseats the check valves, 16, and passing into the piston chambers, 2, raises the pistgns, 10, thereby unseating the valves, 9, and admitting steam from the boiler to the distribution tal chests, through the 7. The valve l and 16, piston, 10,

15, are properly proporto the distribution valve chests to maintain approxiand leakage port,

mately atmospheric pressure therein. When the locomotive is stopped, there will be only atmospheric pressure in the tubular extenions, 2-, and the entrapped fluid in the piston chambers, 2, will escape therefrom through the leakage ports, thereby permitting the pistons, 10, to' fall to their lowest position, and the yalves, 9, to seat themselves, and prevent1ng further flow of boiler steam to the distributlon valve chests.

We claim as our-invention and desire to secure by Letters Patent:

1. In a drifting valve appliance for locomotives, the combination of a valve controlling the supply of steam from a locomotive boiler to .a steam cylinder, independently of the main steam supply pipe, a piston adapted to unseat said valve, and means, automatically operable by the cessation of main steam pipe supply, for admitting cylinder pressure to said piston.

2. In a drifting valve appliance for locomotives, the combination of a passage estab llshing communication between alocomotive boiler and a steam cylinder, independently of the main steam supply pipe, a valve'controlling said passage, a piston adapted to unseat said valve, and a check valvesubiect to cylinder pressure and controlling the admission of said pressure to the piston.

3. In-a driftin valve ap liance for locomotives, the com ination o avalve casing having connections'to the steam space of a locomotive boiler, to a locomotive cylinder, and to a distribution valve chest, respectively, a valve in said casing, controlling communication betwe'en the boiler connection and the valve chest connection, and

means for unseating said valve by pressure from the cylinder connection.

4. In a drifting valve appliance for locomotives, the combination of a valve casing having connections to the steam space of a locomotive boiler, to a locomotive cylinder,

and toa distribution valve chest, respectively, a valve chamber in said casin continuously open to the boiler connection, a piston chamber in said casing continuously open to thevalve chest connection, a valve controlling communication between the valve chamber and the piston chamber, a

iston fitting in the iston chamber and adapted to unseat said valve, and a valve controlling the admission of pressure from controlling the cylinder connection to the piston chamber. Y

5. In a driftin valve appliance for locomotives, the com ination of a valve casing having connections to the steam space of a locomotive boiler, to a'locomotive cylinder,

and to a distribution valve chest, respectively, a valve chamber in said casing continuously open to the boiler connectlon, a

piston chamber in said casing continuously open to the valve chest connection, a valve controlling communicatlon between the valve chamber and the piston chamber, a

piston fittingin the piston chamber and adapted to unseat said valve, a valve controlling the admission of pressure from the cylinder connection to the piston chamber, and means for releasing pressure from the piston chamber upon the closure of said valve.

6. In a driftin valve appliance for locomotives, the com ination of a valve casing having connections to the steam space of a locomotive boiler, to a locomotive cylinder, and to a distribution valve chest, respectively, a valve chamber in said casin con.- tinuousl open to the boiler connect on, a piston c amber in said casing continuously open to the valve chest connection, a valve communication between the valve chamber and the piston chamber, a piston fitted in the piston chamber and adapted to unseat said valve, a partition interposed between the piston chamber and the cylinder connection, a valve seat fixed in said partition and having a through passage, a peripherally perforated guide fit chamber Within the guide, and a leakage port extending, through the partition, from the piston chamber to the cylinder connection.

ROBERT RENNIE.

HAL R. STAFFORD.

Witnesses as to Robert Rennie:

W. SEMPLE, F. K. BAREIS.

\Vitnesses as to Hal R. Stafford:

J. SNOWDEN BETT, EDv'vARD A. WRIGHT. 

